diff --git a/sqlalchemy_opentracing/__init__.py b/sqlalchemy_opentracing/__init__.py
index cb77c1a..ad42b6f 100644
--- a/sqlalchemy_opentracing/__init__.py
+++ b/sqlalchemy_opentracing/__init__.py
@@ -5,14 +5,19 @@
 g_tracer = None
 g_trace_all_queries = False
 g_trace_all_engines = False
+g_flask_tracer = False
+g_origin_tracer = None
 
-def init_tracing(tracer, trace_all_engines=True, trace_all_queries=True):
+
+def init_tracing(tracer, trace_all_engines=True, trace_all_queries=True, flask_tracer=False):
     '''
     Set our global tracer.
     Tracer objects from our pyramid/flask/django libraries
     can be passed as well.
     '''
-    global g_tracer, g_trace_all_engines, g_trace_all_queries
+    global g_tracer, g_trace_all_engines, g_trace_all_queries, g_flask_tracer, g_origin_tracer
+
+    g_origin_tracer = tracer
 
     if hasattr(tracer, '_tracer'):
         tracer = tracer._tracer
@@ -20,10 +25,12 @@ def init_tracing(tracer, trace_all_engines=True, trace_all_queries=True):
     g_tracer = tracer
     g_trace_all_queries = trace_all_queries
     g_trace_all_engines = trace_all_engines
+    g_flask_tracer = flask_tracer
 
     if trace_all_engines:
         register_engine(Engine)
 
+
 def get_traced(obj):
     '''
     Gets a bool indicating whether or not this
@@ -31,6 +38,7 @@ def get_traced(obj):
     '''
     return getattr(obj, '_traced', False)
 
+
 def set_traced(obj):
     '''
     Mark a statement/session to be traced.
@@ -46,6 +54,7 @@ def set_traced(obj):
         # after commit/rollback.
         _register_connection_events(obj)
 
+
 def clear_traced(obj):
     '''
     Clear an object's decorated tracing fields,
@@ -56,11 +65,17 @@ def clear_traced(obj):
     if hasattr(obj, '_traced'):
         del obj._traced
 
+
 def get_parent_span(obj):
     '''
     Gets a parent span for this object, if any.
     '''
-    return getattr(obj, '_parent_span', None)
+    parent_span = getattr(obj, '_parent_span', None)
+    # use flask_tracer current span as default parent span
+    if parent_span is None and g_flask_tracer:
+        parent_span = g_origin_tracer.get_span()
+    return parent_span
+
 
 def set_parent_span(obj, parent_span):
     '''
@@ -70,6 +85,7 @@ def set_parent_span(obj, parent_span):
     obj._parent_span = parent_span
     set_traced(obj)
 
+
 def has_parent_span(obj):
     '''
     Get whether or not the statement has
@@ -77,6 +93,7 @@ def has_parent_span(obj):
     '''
     return hasattr(obj, '_parent_span')
 
+
 def register_engine(obj):
     '''
     Register an engine to have its events be traced.
@@ -90,6 +107,7 @@ def register_engine(obj):
     listen(obj, 'after_cursor_execute', _engine_after_cursor_handler)
     listen(obj, 'handle_error', _engine_error_handler)
 
+
 def unregister_engine(obj):
     '''
     Remove an engine from having its events being traced.
@@ -98,6 +116,7 @@ def unregister_engine(obj):
     remove(obj, 'after_cursor_execute', _engine_after_cursor_handler)
     remove(obj, 'handle_error', _engine_error_handler)
 
+
 def _clear_tracer():
     '''
     Set the tracer to None. For test cases usage.
@@ -105,6 +124,7 @@ def _clear_tracer():
     global g_tracer
     g_tracer = None
 
+
 def _can_operation_be_traced(conn, stmt_obj):
     '''
     Get whether an operation can be traced, depending on its
@@ -173,6 +193,7 @@ def _engine_before_cursor_handler(conn, cursor,
 def _engine_after_cursor_handler(conn, cursor,
                                       statement, parameters,
                                       context, executemany):
+
     span = getattr(context, '_span', None)
     if span is None:
         return
@@ -243,3 +264,4 @@ def _session_after_begin_handler(session, transaction, conn):
 def _session_cleanup_handler(session):
     clear_traced(session)
 
+